Mobile communication subscribers are annually increasing and mobile communication technologies are also developing. A mobile communication device uses recently Long Term Evolution (LTE) as well as Code Division Multiple Access (CDMA). Wideband Code Division Multiple Access (WCDMA) as a mobile communication standard. The mobile communication device also uses Global Positioning System (GPS) and Wi-Fi.
The mobile communication device like a smartphone prefers a built-in antenna to an external antenna. The built-in antenna includes an inverted F antenna, a Planar inverted F antenna, an Inverted L antenna, and a Planar inverted L antenna, etc.
Further, the smartphone is required to process signals from various frequency bands according to a trend of the multi-functionality. Therefore, there is a necessity for the smartphone to be optimized for a low-frequency signal and a high-frequency signal and to minimize the transmission loss of the signal in the transmission/reception of the signal.